You have received an air quality alert. And now?

If you’re in the United States this summer, you might notice an increase in air quality alerts coming to your phone. As we saw last summer – when wildfires in Canada left much of the East Coast suffering from smoke and smog, not to mention hazy, orange skies in New York City – air quality is expected to be affected by seasonal changes. On the one hand, forest fire season has become more frequent and intense, a pattern that experts expect will continue as climate change creates warmer conditions. But other factors can also contribute to air pollution, which is associated with negative health effects, especially for certain vulnerable groups.

How can you stay safe and what should you do if your area has poor air quality? Here’s what you should know.

What does an air quality alert mean?

An air quality alert is a notification given by various public health authorities, including state and local air quality agencies, that alerts the public when air pollution reaches unhealthy levels. You can sign up for receive alerts on your phone from the Environmental Protection Agency.

O Air Quality Index (AQI) is the system that alerts the public when air pollution is dangerous. The different levels of air quality advice range from the green “good” level to the brown “dangerous” level.

There are about 4,000 monitoring stations owned and operated primarily by state environmental agencies and regulated by the EPA, which submit hourly or daily measurements of these major air pollutants:

• Tropospheric ozone

• private matter

• Carbon monoxide

• sulfur dioxide

• nitrogen dioxide

Ozone and particulate matter pose the greatest threat to public health, Peter DeCarlo, associate professor of environmental health and engineering at Johns Hopkins University, told Yahoo Life.

When particulate matter — defined by EPA as “a mixture of solid particles and liquid droplets found in the air” – reaches levels that exceed unhealthy levels for the public, triggers an alert.

“People are probably familiar with this because of wildfires,” says DeCarlo.” That kind of haze that you see in the air and the particles in the air are particles.” In fact, air quality advisories for Montana, North Dakota, South Dakota and Minnesota were issued on May 13 as wildfires in Canada sent heavy plumes of smoke into the region, creating hazy conditions.

Meanwhile, ozone – defined by EPA as “highly reactive natural and man-made gas…occurring in Earth’s upper atmosphere (the stratosphere) and lower atmosphere (the troposphere) – worsens in the US during the summer due to increased sunlight.

“Ozone is formed by chemistry that occurs in the atmosphere… and summer conditions – where it’s hot and there’s a lot of sunlight – kind of push that chemistry to go faster and produce more ozone,” explains DeCarlo. “That’s why it’s in the summer that we see ozone [and] air quality alerts.

How can poor air quality affect health?

Yes, say the experts. Marianthi-Anna Kioumourtzoglouassociate professor of environmental health sciences at Columbia University’s Mailman School of Public Health, told Yahoo Life that when a person breathes in pollutants, the particles produce local oxidative stress – an imbalance between free radicals and antioxidants in your body – and inflammation in the lungs, which can spread throughout the body.

According to Kioumourtzoglou, air pollution has been linked to “adverse” cardiovascular, pregnancy and neurodevelopmental outcomes. Experts also told Yahoo Life last year that research has linked pollution exposure to behavioral and cognitive problems in babies and young children, while the effects of wildfire smoke have been linked to a greater risk of premature birth and lower birth weight. Air pollution can also worsen asthma symptoms, such as wheezing.

What to do if you receive an air quality alert

If you receive an air quality alert, pay attention to the color code: the darker the color, the more necessary it is to stay home. Experts also advise people to plan outdoor activities such as exercising or lawn care at times when ozone levels are lowest, generally in the morning and evening.

Here are some ways to stay safe if you receive an alert:

• Limit outdoor activities, especially if you belong to “sensitive groups”, including children, people with heart and lung disease, respiratory problems, pregnant women and the elderly

• Wear a mask if you must be outdoors

• Minimize outdoor exercise to avoid taking deep breaths in poor air quality conditions

• Keep pets indoors

• Turn on the air conditioning to recirculate indoor air

• Monitor online tools like Purple Air that share real-time air quality data

Kioumourtzoglou recognizes that while it’s important to avoid air pollution in general, many people don’t have the option to stay at home.

“One of those things is that, unfortunately, people who work outside the home also have a lower socioeconomic status, potentially, and may already be at higher risk for disease,” says Kioumourtzoglou. “Many of us can’t move houses if we live near a highway and we can’t install filters in our homes because all these things cost [money] and we may not be able to afford these things.”