It wouldn’t seem like cement in the air would be a problem; maybe cement in the soil … if in large quantities. But remember that hydrangeas are susceptible to disease. This page from the Alabama Cooperative Extension service (more on your local in a moment) shows the effects of several problems with hydrangeas and offers some advice to remedy the situation: http://www.aces.edu/pubs/docs/A/ANR-1212/ANR-1212.pdf
If you would like advice from your local cooperative extension service, find your state here and follow through with contact: http://www.almanac.com/content/cooperative-extension-services
If it’s convenient for you, you might also bring a leaf to a local nursery, describe the situation, and see if they have an opinion.
It wouldn’t seem like cement in the air would be a problem; maybe cement in the soil … if in large quantities. But remember that hydrangeas are susceptible to disease. This page from the Alabama Cooperative Extension service (more on your local in a moment) shows the effects of several problems with hydrangeas and offers some advice to remedy the situation: http://www.aces.edu/pubs/docs/A/ANR-1212/ANR-1212.pdf
If you would like advice from your local cooperative extension service, find your state here and follow through with contact: http://www.almanac.com/content/cooperative-extension-services
If it’s convenient for you, you might also bring a leaf to a local nursery, describe the situation, and see if they have an opinion.
We hope this helps!