Pollution in Portland comes from various sources, including vehicle emissions, industrial activities, construction sites, power plants, and residential heating. These activities release pollutants such as carbon monoxide, nitrogen dioxide, particulate matter, and volatile organic compounds into the air.

Poor air quality in Portland can occur due to a combination of factors. Some common reasons include increased vehicle emissions during traffic congestion, industrial activities, wildfires, and stagnant weather conditions that trap pollutants close to the ground, as well as the presence of pollutants blown in from other areas.

Ambee measures Portland's air quality using the city’s monitoring stations, which are located throughout the city. These stations collect data on various pollutants in the air, such as particulate matter, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide. The data are then used to calculate the AQI.

The Air Quality Index (AQI) is a numerical scale that indicates the overall level of air quality. It provides information about how clean or polluted the air is and the associated health risks. The AQI in Portland ranges from 0 to 500, with higher numbers indicating poorer air quality. Different color categories (green, yellow, orange, red, etc.) are used to communicate the levels of health concern associated with the AQI values.

Air quality refers to the condition of the air, including pollutants and their concentrations. It is important because polluted air can negatively impact human health, the environment, and overall quality of life. Breathing in polluted air can lead to respiratory problems, allergies, heart issues, and other health concerns. Additionally, poor air quality can harm ecosystems, contribute to climate change, and reduce visibility.

To improve air quality in Portland, various measures are being taken. These include promoting the use of electric vehicles and public transportation to reduce vehicle emissions, implementing stricter emission standards for industries and power plants, encouraging energy-efficient practices, supporting renewable energy sources, enforcing regulations to reduce wood smoke, and raising awareness about air quality issues within the community.

Weather conditions, such as wind and temperature, significantly impact air quality in Portland. Wind disperses pollutants, improving air quality, but calm winds can trap pollutants near the ground, leading to poorer conditions. Temperature inversions can also keep pollutants close to the surface, degrading air quality. Additionally, wind patterns and temperature influence wildfire smoke, affecting air quality during wildfire events.