Extreme heat + air pollution can be deadly, with the health risk together worse than either alone

Bad air pollution and extreme heat each raise health risks, but they’re worse combined. Brian van der Brug/Los Angeles Times via Getty Images

by Erika Garcia, University of Southern California; Md Mostafijur Rahman, University of Southern California, and Rob Scot McConnell, University of Southern California

On the morning news, you see the weather forecast is for high heat, and there is an “excessive heat watch” for later in the week. You were hoping the weather would cool down, but yet another heat wave is threatening human health and increasing the chance of wildfires. On top of these warm days and nights, air quality data has been showing unhealthy levels of pollution.

Sound familiar? This scenario is increasingly the new normal in many parts of the world.

High heat and air pollution are each problematic for human health, particularly for vulnerable populations such as older adults. But what happens when they hit at the same time?

We examined over 1.5 million deaths from 2014 to 2020 registered in California – a state prone to summer heat waves and air pollution from wildfires – to find out.

Deaths spike when both risks are high

The number of deaths rose both on hot days and on days with high levels of fine particulate air pollution, known as PM2.5. But on days when an area was hit with a double whammy of both high heat and high air pollution, the effects were much higher than for each condition alone.

The risk of death on those extra-hot and polluted days was about three times greater than the effect of either high heat or high air pollution alone.

The more extreme the temperatures and pollution, the higher the risk. During the top 10% of hottest and most polluted days, the risk of death increased by 4% compared to days without extremes. During the top 1%, it increased by 21%; and among older adults over age 75, the risk of death increased by more than a third on those days.

Why risks are higher when both hit at once

There are several ways the combined exposure to extreme heat and particulate air pollution can harm human health.

Oxidative stress is the most common biological pathway linked with particulate air pollution and heat exposure. Oxidative stress is an imbalance between production of highly reactive molecules known as reactive oxygen species, or ROS, and the body’s ability to remove them. It’s been linked with lung diseases, among other illnesses.

Antioxidants help clean up these molecules, but particulate air pollution and heat disrupt this balance through excessive metabolic ROS production and lowered antioxidant activity.

Our research also showed that the effects of particulate air pollution and heat extremes were larger when high nighttime temperature and pollution occurred together. High nighttime temperatures can interfere with normal sleep and potentially contribute to chronic health conditions such as heart disease and obesity, and disrupt how the body regulates temperature.

Older adults may be more susceptible to effects of extreme heat and air pollution exposure, in part because this stress comes on top of age-related chronic health conditions like heart disease, high blood pressure, diabetes or chronic lung disease. Impaired body temperature regulation in response to heat can also occur with aging. And older adults may be less mobile and therefore less able to get to cooling centers or to medical care and be less able to afford air conditioning.

A future of high temperatures and air pollution

This isn’t just a California problem. Climate change will increase exposure to high heat and air pollution in many parts of the country.

Yearly average temperatures in the U.S. are already more than 1.8 degrees Fahrenheit (1 degree Celsius) warmer than at the beginning of the 1900s. By the end of this century, global temperatures are on pace to be nearly 5 F (2.7 C) warmer. Dangerous extreme heat waves, currently rare, will become more common.

Changing climate is also affecting levels of outdoor fine particulate pollution – for example, through weather changes such as air stagnation events, wind and dust storms, and drier and warmer conditions that contribute to increasingly frequent and intense wildfires.

What to do to stay safe

Further research is needed to better understand these effects, such as the full impact of wildfire smoke exposure. However, enough is known that people should take measures to reduce their risk of harm during periods of extreme heat or air pollution.

That means staying well hydrated and keeping cool. Shopping malls and other air-conditioned public spaces can provide a refuge from heat. Home air conditioning, especially during nighttime, can reduce mortality. A portable air filter in the bedroom can markedly reduce particle pollution levels.

People with symptoms of heat stress, such as headache, nausea, dizziness or confusion, especially the elderly, should seek medical care.

Many county and state health departments already provide alerts about extreme heat and extreme air pollution. Developing a special category of alert during co-occurring extremes may be beneficial to public health.

Governments also need to take steps now to avoid the worst future climate change scenarios. Some best practices for cities include creating cooling shade cover and green space that will also reduce particle pollution.

This article was updated Aug. 31, 2022, with heat advisories in the West.

Erika Garcia, Assistant Professor of Population and Public Health Sciences, University of Southern California; Md Mostafijur Rahman, Postdoctoral Scholar and Research Associate in Environmental Health, University of Southern California, and Rob Scot McConnell, Professor of Population and Public Health Sciences, University of Southern California

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Environmental groups call for air monitoring, home air filtration systems in Little Village two years after botched implosion

Read the full story in the Chicago Sun-Times.

Environmental community groups issued a list of demands Monday as they continue to seek answers about the demolition of a smokestack at the former Crawford Coal Plant.

EPA research improves air quality information for the public on the AirNow Fire and Smoke Map

Read the full story from U.S. EPA.

Air sensors, more portable and easier to use than conventional regulatory air monitors, have become increasingly popular for measuring air pollution across the United States, particularly during wildfires. Researchers and communities have used air sensors to fill gaps in understanding local air quality. However, these sensors can often incorrectly estimate pollutant levels compared to regulatory-grade monitors. EPA researchers want to make it easier to compare the data from air sensors with data from highly accurate monitors. To do this, they have collocated, or placed sensors side-by-side with accurate regulatory monitors, in several locations throughout the country.

One widely used sensor type, the PurpleAir, was tested at more than 70 locations throughout the United States by EPA researchers and more than 30 state, local, and tribal air agency partners. While there are several options for air sensors on the market, the popularity of PurpleAir sensors meant the researchers could tap into a widespread sensor network spanning the country. Using this data, EPA researchers developed a mathematical equation, called a “correction equation,” to adjust the air sensor data, making the making the data more accurate and comparable to the regulatory network.

Google Maps now helps you find fresh air

Read the full story at The Verge.

Google Maps on both iOS and Android has a new Air Quality layer that can be useful when planning your next hike or bike ride in good times, or to plan your escape from smog and smoke in bad.

The new layer displays an Air Quality Index (AQI) overlay directly onto the map grid using government data gathered from agencies like the EPA in the US to show how healthy the air is in general. Better yet, it also presents data collected from PurpleAir’s network of sensors to report hyperlocal conditions at the street level. Clicking on the AQI readings dotted around Google Maps provides more information on the health impact of the air quality, time and source of the last reading, and links to learn more.

Is your neighborhood’s air polluted? New website tracks air quality across the St. Louis region

Read the full story in the St. Louis Post-Dispatch.

A new website launched Tuesday enables the public to track air quality in St. Louis neighborhoods, thanks to a network of monitors stationed primarily on churches around the region.

The site, called AirWatch St. Louis, provides up-to-the-hour data about current conditions and specific pollutants. Groups behind the project say it’s information “that researchers, residents and community leaders can use to address health problems that have plagued historically disenfranchised neighborhoods for generations,” according to an announcement Tuesday.

Webinar: Clear the Air: Healthy Indoor Air for Businesses and Tenant Spaces

Jun 28, 2022 10 am CDT
Register here.

This webinar will discuss ways small business owners and building managers can ensure healthy indoor air quality for staff and customers.

Speakers

  • Scott Williams, Williams Building Systems Engineering
  • John Zai, University of Colorado, Boulder

Air pollution more likely to harm people of color in Wisconsin, especially in Milwaukee, study finds

Read the full story in the Milwaukee Journal Sentinel.

People of color in Wisconsin are more likely to be exposed to harmful air pollution than white people, creating the third-largest disparity in the country, according to a state environmental advocacy group. 

Clean Wisconsin analyzed data from a recent study from the University of Illinois, which calculated the exposure to fine particulate matter in the air among different racial-ethnic groups. The study, overall, found that people of color are exposed to more particulate air pollution than white residents. 

In Wisconsin, analysts found one of the largest racial disparities between the impacts of dangerous particulate matter. 

Community-led science uncovers high air pollution from fracking in Ohio county

Read the full story from the Columbia Climate School.

Some residents of Belmont County in eastern Ohio have long suffered from headaches, fatigue, nausea and burning sensations in their throats and noses. They suspected these symptoms were the result of air pollution from fracking facilities that dominate the area, but regulators dismissed and downplayed their concerns.

With the technical assistance of volunteer scientists at Columbia University’s Lamont-Doherty Earth Observatory, MIT and the American Geophysical Union’s Thriving Earth Exchange, local advocacy groups set up their own network of low-cost sensors. They found that the region’s three EPA sensors were not providing an accurate picture: The sensors revealed concerning levels of air pollution, and correlations between local spikes and health impacts.

The results are published today in the journal Environmental Research Letters.

Why Indoor Chemistry Matters

Download the document.

People spend the vast majority of their time inside their homes and other indoor environments where they are exposed to a wide range of chemicals from building materials, furnishings, occupants, cooking, consumer products, and other sources. Despite research to date, very little is known about how exposures to indoor chemicals across complex chemical phases and pathways affect human health. The COVID-19 pandemic has only increased public awareness of indoor environments and shed light on the many outstanding questions about how best to manage chemicals indoors. This report identifies gaps in current research and understanding of indoor chemistry and new approaches that can be applied to measure, manage, and limit chemical exposures. Why Indoor Chemistry Matters calls for further research about the chemical transformations that can occur indoors, pathways and timing of indoor chemical exposure, and the cumulative and long-term impacts of exposure on human health. Research priorities should consider factors that contribute to measurable environmental health disparities that affect, vulnerable populations, such as the age, location, and condition of buildings that can alter exposures to indoor chemicals.

Measurement and Monitoring Methods for Air Toxics and Contaminants of Emerging Concern in the Atmosphere grants

Read the full story from U.S. EPA.

EPA’s Science to Achieve Results Program (STAR) awarded over $4 million to seven universities to advance air measurement and monitoring methods for air toxics and contaminants of emerging concern in the atmosphere.

Hazardous air pollutants (HAPs), often referred to as air toxics, are a subset of air pollutants known or suspected to be acutely toxic or cause chronic human health effects, or to have adverse environmental and ecological effects. Contaminants of emerging concern are chemicals that are not commonly monitored in the environment but are present in the environment and have the potential to cause adverse human health or environmental effects. These air contaminants tend to pose greater risks in urban areas because these areas have large populations and a higher concentration of emission sources, and there is extensive evidence that minority and low-income communities are disproportionally burdened with exposures to air toxics. 

The goals of this research portfolio include advancements in measurement techniques that will support state, community and Tribal air monitoring efforts to reduce exposures to air toxics and emerging contaminants of concern and to address environmental justice issues; and improved source measurement methods that can be used to quantify emissions, develop emissions inventories, inform the development of effective emission control strategies, and ultimately improve public health.