Tired of pollution drifting up from the south, officials in Toronto, Canada’s largest city, are considering joining a lawsuit that New York state plans to file next month against coal-fired power plants in the Midwest. Toronto health and environment officials are to meet today with the office of New York’s attorney general, which last month announced plans to sue 17 power plants in Indiana, Kentucky, Ohio, Virginia, and West Virginia. Emissions from the plants drift into New York, contributing to asthma problems and damaging forests, wildlife, and waterways, says the attorney general’s office. Toronto officials say the emissions also raise smog levels in their city.