The summer often comes with talk of air quality concerns, especially in the city. This week, we’re facing a double threat — Canadian wildfire smoke that could compound any issues from the high heat and humidity. The smoke is expected to stick around, and air quality alerts are in place. So, is it safe for you to be outside? The number most often used to assess that is the Air Quality Index (AQI). Right now, all New York regions are expected to hit at least the “unhealthy for sensitive groups” threshold in terms of air quality by the end of the day Wednesday. Air in parts to the north, including the state’s Central Region, may be hazardous at times. Simply put, the numbers show how clean or polluted the air is, or how many pollutants are present, according to the New York State Department of Environmental Conservation. While the numbers don’t directly represent the number of pollutants in the air (for example, an AQI of 300 doesn’t mean there are 300 pollutants in the air), the number is more of a yardstick to show pollution levels. The higher the AQI value, the greater the level of air pollution and the greater the health concern, according to AirNow. The scale goes from 0 to 500, with 500 being the worst. The AQI measures five major air pollutants, according to AirNow. Those are: ground-level ozone particle pollution (also known as particulate matter) carbon monoxide sulfur dioxide nitrogen dioxide Fine particle pollution from wildfire smoke can cause shortness of breath, coughing, dizziness or fatigue, and aggravate heart and lung diseases and other chronic health issues.  Experts suggest reducing or eliminating outdoor activities, wearing an N95 mask if you have to be outside, and keeping your indoor air cleaner by closing windows and running an air purifier or air conditioner. Long-term exposure to fine particulate matter from wildfire smoke is one of the leading causes of premature death. ...read more read less