High Heat and Air Quality: What’s the Connection?

Summer heat and poor air quality

With extreme heat comes poor air quality. What is the connection between the two? We take a look at why pollution and ozone increase on hot summer days.

For those who experience changing seasons, summertime brings warm temperatures and highly anticipated outdoor activities. While Chicago is known for its extremely frigid winters, summertime sees its fair share of high heat days. Some of these days are so hot and humid that it is almost unbearable to enjoy any activities outdoors. In fact, this past weekend, Chicago experienced a heat advisory when temperatures and humidity rose to dangerous levels and a 110-degree heat index.

When experiencing these uncomfortable heat waves, an accompanying air quality advisory is often issued. Air quality advisories are common in places of constant summertime heat like southern California and parts of the northeast. The question is, are heat and poor air quality connected?

High Heat & Poor Air Quality: A Multi-faceted Problem

Summer heat in the city producing poor air quality

The short answer to the question asked above: yes. On hot days, particulate pollution tends to rise above the air quality index healthy air standard and more widespread ozone occurs. The more detailed explanation of why this occurs takes into account several factors such as geography, urban life, and industry presence.


Los Angeles tends to top list after list each year as one of the worst offenders of cities with high air pollution. Although the region is highly populated and industrialized, its location is a primary factor in its pollution levels. Broad valleys surrounded by mountains like the Los Angeles basin traps the pollutants from highways, ports, and factories, creating extensive smog and poor air quality.

Chicago, famously known as the ‘windy city’ (albeit windy, not the source of the name!), gets much of its heat from the Great Plains sizzle,’ where southwest winds from the plains bring hot air to the city. A defining factor of Chicago summers, humidity is brought up from the Gulf of Mexico. Although breezes off Lake Michigan can be a nice break from the heat, there are days when there is hardly a breeze and the hot and humid air sits, creating a very uncomfortable situation for Chicagoans. This occurred over the weekend while air quality alerts were issued.

Urban Life and Industry

Have you ever noticed a haze settling in over a city skyline on particularly hot and humid days? That haze develops when ozone levels increase, creating smog. High temperatures and sunlight basically bake the air and any chemical compounds (pollution) lingering in it. This chemical soup combines with the naturally occurring nitrogen oxide in the air, creating a “smog” of ground-level ozone gas.

What is ozone? Ozone is a gas generated when pollution from vehicle tailpipes, power plants, and factories bakes in sunlight.  High up in the atmosphere, ozone protects living things on Earth from the sun’s harmful UV radiation, but at ground level, ozone is harmful to humans, plants, and animals.

In addition to the dangers of extreme heat, increased ground-level ozone is harmful to many people with existing breathing problems including children and the elderly. Ozone, or smog, can cause throat irritation, congestion, chest pain, trigger asthma, inflame the lining of the lungs, worsen bronchitis and emphysema and reduce lung function.

What To Do During An Air Quality Alert

Summer heat can be brutal in city apartments

While spending time outdoors enjoying the summer fun may be on your to-do list, it is important to take the necessary precautions during an air quality alert.

Here are some helpful guidelines to consider for these high-risk days:

  • Reduce your contribution to pollution by taking public transportation, rideshare, walk, or bike
  • Remain cool and reduce physical activity outdoors
  • Turn off lights and unplug unnecessary electronics to reduce energy consumption
  • Use environmentally friendly cleaning products
  • Avoid burning anything outdoors like charcoal or leaves
  • Beat the heat and bad air by staying indoors. Ensure you are taking the necessary steps to healthy indoor air by running a Venta Humidifier, which humidifies your indoor air while it naturally reduces indoor air pollutants.
    • Humidity may be the last thing on your mind during a heatwave, but when it comes to indoor air in the summer, dry air-conditioned air sure takes its toll on your health and skin.
    • Unlike most humidifiers, the Venta Humidifier will never over-humidify, so you never have to worry about damp floors and over-saturated air. While it feels good to cool off in front of an air conditioner or fan, remember to knock out dry air with a humidifier. Your health and skin will thank you later!
    • As we’ve written about before, indoor air can be as dangerous to your health as much as outdoor air is. With the Venta Humidifier’s patented cold evaporation technology, airborne pollutants in your indoor air will be trapped in the unit while only pure, clean air is released. Because the humidifier does not use filters to improve your indoor air, no trash is produced, making the unit both a hygienic and green product.

Have you experienced a high heat and poor air quality day yet this summer? What precautions do you take to beat the heat and pollution?