Sunshine, rain, higher temperatures, wind speed, air turbulence, and mixing depths all affect pollutant concentrations.
While industrial emissions remain mostly constant throughout the year, particulate matter and carbon monoxide pollutants from wood burning increase during the cold winter months. Idling cars to defrost or keep them warm increases the amount of air pollution as well.
But artificial light at night (ALAN) also interacts with the air itself, changing its chemistry. Those changes can reduce air quality and impact public health.
TL;DR — Because air quality is impacted by factors such as temperature and weather patterns, certain aspects of the summer season lead to heightened air pollution levels. Increased sunlight levels can contribute to higher ground-level ozone, smog, and nitrogen dioxide levels — and, thus, harm human health.
In the last several years, a growing body of scientific evidence has indicated that the air within homes and other buildings can be more seriously polluted than the outdoor air in even the largest and most industrialized cities.
Poor indoor air quality (IAQ) has been tied to symptoms like headaches, fatigue, trouble concentrating, and irritation of the eyes, nose, throat and lungs. Also, some specific diseases have been linked to specific air contaminants or indoor environments, like asthma with damp indoor environments.
Increased Oxygen
The air indoors can have a poor balance of oxygen, nitrogen, and carbon dioxide. The air quality indoors can get worse in rooms with poor ventilation. The fresh air outside usually has higher levels of oxygen and lower levels of pollution.
Air Quality in the Morning vs Nighttime
According to one study, air quality is worse at night for several reasons. First, body heat and movements when you sleep cause bedding, mattresses, and pillows to emit air pollutants that negatively affect our health.
Scientists have long known that when common pollutants from traffic exhaust get cooked by the sun, they get transformed into ozone and particulates, two “secondary” pollutants that are harmful to human health.
Rain, snow, and wind can significantly help reduce air pollution. Rain and snow helped lower measurements of PM2. 5 in Los Angeles and San Francisco, California; Portland, Oregon; Denver, Colorado; and Salt Lake City, Utah.
As lighting accounts for nearly 10% of residential electricity use [3], reducing the total energy used by lighting has the potential to decrease carbon dioxide emissions.
With emptier streets and quieter factories, air quality at night is easily perceived as being better than during the day. However, air quality is often at its worst in the early evening hours, with PM2.5 levels peaking between 21:00 and 23:00 globally4.
Air pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere. Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution.
If outdoors, sensitive groups should keep activities light and avoid activities over 2 hours. Consider moving practices and events indoors. If events are not cancelled, increase rest periods to allow for lower breathing rates. Everyone should remain indoors as much as possible.
Usually the most effective way to improve indoor air quality is to eliminate individual sources of pollution or to reduce their emissions. Some sources, like those that contain asbestos, can be sealed or enclosed; others, like gas stoves, can be adjusted to decrease the amount of emissions.
The Sun's radiation strikes the Earth's surface, thus warming it. As the surface's temperature rises due to conduction, heat energy is released into the atmosphere, forming a bubble of air that is warmer than the surrounding air.
The heat and humidity of the summer can result in poor air quality, both outdoors AND indoors. Sunlight and solar radiation can produce more ozone in the air we breathe, which is dangerous. Pollution like nitrogen oxides react with other chemicals and hydrocarbons in the sunlight to form ozone gas.
The outdoor air pollution is significantly more serious when the fog and haze occurs. Avoid windows opening before the presence of a high visibility of ambient air.
Air Quality in the Morning Vs Nighttime
Researchers discovered that particulate matter concentrations are greater in the morning and at night. It is especially active between 7:00 and 10:00 a.m. and 9:00 and 11:00 p.m. (LST). On the other side, it is lowest in the afternoon, particularly from 3:00 and 5:00 PM (LST).
At night, there's typically less wind. During the day, the sun heats up the ground, causing the air to rise and creating wind. On the other hand, at night time, the ground cools down which reduces the wind speed. With less wind to disperse pollutants, they tend to accumulate and settle near the surface.
Oxygen in air is about 21%. Purification removes particulates and may make air smell cleaner or crisper. This may give the impression that there is more oxygen, but the percentage remains the same.
Fresh air not only cleans your lungs, it can also boost your mood, lower your heart rate, increase energy levels and even improve digestion (yes, that's right). Florence Nightingale knew the benefits of fresh air long before any scientific study.
So changes would be even smaller in most homes. Simply put, humans don't take in as much oxygen as we think we do. Based on oxygen alone, estimates are that the average person could survive in a completely sealed, airtight room for 12 full days! Running out of oxygen in a room is quite unlikely.