Supported by Smoke from Canadian wildfires and desert dust from the Sahara are creating unhealthy air quality from New York City to Miami. By Nazaneen Ghaffar and Amy Graff Nazaneen Ghaffar and Amy Graff are reporters on The Times’s weather team. Wildfire smoke from Canada and plumes of desert dust from the Sahara are smothering large portions of the United States, creating hazy skies and hazardous air quality from the Northeast to the Southeast. The National Weather Service issued air quality alerts on Wednesday for New York City and many surrounding areas, including New Jersey and most of Connecticut. Officials said that those more sensitive to air pollution should limit going outdoors and watch for respiratory symptoms from 11 a.m. to 11 p.m. Air quality in the New York City metro area and the Lower Hudson Valley was forecast to be “unhealthy for sensitive groups,” according to the New York State Department of Environmental Conservation. The department had air quality health advisories in effect for these areas, especially for at-risk individuals. The general public, it said, was less likely to be affected. Elsewhere in New York, including on Long Island, air quality levels were expected to be “moderate.” The U.S. Environmental Protection Agency warns that wildfire smoke contains dangerous pollutants in the form of fine particles known as PM 2.5 that can penetrate deep into the lungs and enter the bloodstream. Short-term exposure can lead to bronchitis, worsen asthma and create other health issues. Several air quality warnings were also in effect in Western Canada for areas around the fires in that part of the country, with smoke billowing toward northwest Ontario. Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times. Thank you for your patience while we verify access. Already a subscriber? Log in. Want all of The Times? Subscribe.