​Major League Baseball’s seemingly annual midsummer conflict with smoke from Canadian wildfires could impact the start of the second half for several teams.The Philadelphia Phillies moved up the start of their Thursday, July 16 game against the New York Mets from 7:05 to 6:10 p.m. ET, with air quality expected to worsen as the night continues from Citizens Bank Park. The air quality index 45 minutes before game time was 176, or very unhealthy. It is scheduled to peak at 180 by 9 p.m., according to Accuweather, as the Phillies and Mets play the lone game on the schedule following the All-Star break.AdvertisementAdvertisementAdvertisementYet MLB faces more significant problems Friday.With all 30 teams in action, air quality is forecast in the “dangerous” range as games begin in Cleveland, Chicago and Milwaukee. The Guardians play host to the Pittsburgh Pirates at 7:10 p.m. in Cleveland, where the current air quality is 350 and forecast to be 313 at game time Friday.It is the same story in Chicago, where Major League Soccer’s Fire postponed their Thursday game with the air quality at 597. It has since dropped to 304, still in the dangerous range, and is projected to remain at 299 as the Cubs prepare to open the second half with a 7:05 p.m. CT start against the Minnesota Twins.1 / 8Fans look on before the All-Star Game at Citizens Bank Park.(Brad Penner, Imagn Images)The dangerous, or hazardous plateau begins at 301, which constitutes a health warning and outdoor activities are strongly discouraged, per the Environmental Protection Agency’s standards. The Mets and Phillies are scheduled to play Thursday under a red, or “unhealthy” advisory, which the EPA defines as “some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.”AdvertisementAdvertisementAdvertisementIn Milwaukee, the AQI is at 337 and expected to maintain a similar level before the Brewers play host to Miami on Friday night.MLB has postponed or moved games on two occasions in recent years due to air quality. On June 7 and 8, games were postponed in New York, Philadelphia and Washington due to poor air quality. In 2020, a Seattle Mariners game was postponed – and then relocated to San Francisco – after the Mariners and Athletics played through poor conditions.The league does not hew exclusively to AQI in making such calls. Yet there are numerical thresholds where protocols and levels of scrutiny go into place, triggering deeper dives into current conditions and projected changes in air quality as MLB, in conjunction with the MLB Players’ Association, consults with medical and weather experts.Other markets will appear to avoid the worst of it. The Boston Red Sox and New York Yankees host games Friday evening, but a forecasted changed in wind directions is expected to improve the AQI in New York from 138 (unhealthy) to 56 (poor) by the time the Yankees play host to the Los Angeles Dodgers. Similarly, Boston is