Choose the correct option(s) from the following regarding urban environment.
- Urban canyons increase ventilation by trapping heat and thus enhancing urban heat island effect.
- Program evaluation and review technique (PERT) is always used to estimate the economic impact of mitigation strategies for urban heat island effect.
- In general, land surfaces in urban areas emit more long wave radiation compared to those in rural areas, and thus contribute to higher night time temperature.
- Urban heat island can exacerbate urban flooding by intensifying rainfall intensity.
